Atmel ATtiny25 User Manual

87
7598H–AVR–07/09
ATtiny25/45/85
14.1.5 Timer/Counter1 Output Compare RegisterB - OCR1B
The output compare register B is an 8-bit read/write register.
The Timer/Counter Output Compare Register B contains data to be continuously compared with
Timer/Counter1. Actions on compare matches are specified in TCCR1. A compare match does
only occur if Timer/Counter1 counts to the OCR1B value. A software write that sets TCNT1 and
OCR1B to the same value does not generate a compare match.
A compare match will set the compare interrupt flag OCF1B after a synchronization delay follow-
ing the compare event.
14.1.6 Timer/Counter1 Output Compare RegisterC - OCR1C
The output compare register C is an 8-bit read/write register.
The Timer/Counter Output Compare Register C contains data to be continuously compared with
Timer/Counter1. A compare match does only occur if Timer/Counter1 counts to the OCR1C
value. A software write that sets TCNT1 and OCR1C to the same value does not generate a
compare match. If the CTC1 bit in TCCR1 is set, a compare match will clear TCNT1.
This register has the same function in normal mode and PWM mode.
14.1.7 Timer/Counter Interrupt Mask Register - TIMSK
• Bit 7 - Res: Reserved Bit
This bit is a reserved bit in the ATtiny25/45/85 and always reads as zero.
• Bit 6 - OCIE1A: Timer/Counter1 Output Compare Interrupt Enable
When the OCIE1A bit is set (one) and the I-bit in the Status Register is set (one), the
Timer/Counter1 Compare MatchA, interrupt is enabled. The corresponding interrupt at vector
$003 is executed if a compare matchA occurs. The Compare Flag in Timer/Counter1 is set (one)
in the Timer/Counter Interrupt Flag Register.
• Bit 5 - OCIE1B: Timer/Counter1 Output Compare Interrupt Enable
When the OCIE1B bit is set (one) and the I-bit in the Status Register is set (one), the
Timer/Counter1 Compare MatchB, interrupt is enabled. The corresponding interrupt at vector
$009 is executed if a compare matchB occurs. The Compare Flag in Timer/Counter1 is set (one)
in the Timer/Counter Interrupt Flag Register.
Bit 76543210
$2D ($4D) MSB LSB OCR1B
Read/Write R/W R/W R/W R/W R/W R/W R/W R/W
Initial value00000000
Bit 76543210
$2B ($4B) MSB LSB OCR1C
Read/Write R/W R/W R/W R/W R/W R/W R/W R/W
Initial value11111111
Bit 7 6 5 4 3 2 1 0
$39 ($59) - OCIE1A OCIE1B
OCIE0A OCIE0B TOIE1 TOIE0 - TIMSK
Read/Write R R/W R/W R/W R/W R/W R/W R
Initial value 0 0 0 0 0 0 0 0

Atmel ATtiny25 Specifications

General

Brand	Atmel
Model	ATtiny25
Category	Microcontrollers
Language	English